In general, a blister-packing machine of known type for realizing blister packs is of a type comprising a plurality of work stations arranged in a sequence, among which at least an unwinding station of a first strip made of a heat-formable material, for example plastic or aluminium, in which, by subsequent heat-welding, cells are formed to define a celled strip, a supply station in which a supply unit is destined to controlledly release the products to enable them to be housed in the cells of the celled strip which is advancing below the supply unit, a control station for checking the presence and integrity of the products themselves. Next is an unwinding station of a second strip of heat-weldable material, destined to be used for sealed closing of the celled strip with the cells filled with products, followed finally by a cutting station in which the formation of single blister packs obtained by means of sequential cutting of the celled strip filled with the products.
At present, one of the most critical points in blister machines of the above-described type occurs at the supply station at the stage of release of the products from a mass of products to go internally of the cells of the celled strip.
Although product supply and release units are known which operate optimally such that each cell is correctly filled with a relative product, such as for example the unit described and illustrated in EP patent EP 797,525 B1, or the unit described in U.S. Pat. No. 6,311,743, the operating efficiency of these supply units can considerably diminish, especially at high production speeds or when the celled strip advancing below the supply unit is very fast-moving.
Further, the supply units are often structurally complex and large, such as not to enable a rapid replacement thereof during change-format stages.